The invention relates to a device including a biologically active substance immobilized on a covalent nitride substrate by a bifunctional coupling agent.
The ability to determine quantitatively a substance or a mixture of substances in a given medium is of considerable interest in various applications such as process monitoring, quality control, the determination of pollutants in air and water, the quantitative determination of analytes in physiological fluids, the diagnosis of diseases, the histological compatibility between individuals, food duality and the like. The concentrations of substances to be measured range from molar to picomolar quantities.
There is therefore a need for fast and sensitive detection devices for this purpose.
It has become apparent in particular that it would be advantageous to have available devices in which the biologically active substance is immobilized on an inorganic substrate which is substantially inert as to physical bonding (physisorption) with molecules of said substance and which would also be capable of being incorporated into integrated electronic and/or optical devices. Such materials are lo be found among covalent nitrides such as boron nitride (BN), titanium nitrides, phosphorus nitrides such as P.sub.3 N.sub.5, carbon nitrides, silicon nitrides and transition metal nitrides. Silicon nitride is particularly preferred because of its refractive index, its waveguide properties, its low optical absorption properties and its chemical inertness, which make it well-suited to applications which rely on integrated optics.
In a different technical field, that of surgical Implants or Of surgical hardware, there is a continual need for articles whose surfaces are made biologically compatible, for example in order to minimize or eliminate rejection reactions or adverse reactions of the blood (for example coagulation) in contact with implants and instruments. Although techniques of immobilization) of biologically active substances, for example heparin, are already known, there is still a need for improvements in this field. It has become apparent that nitride coatings, for example titanium nitride coatings, applied to implants or medical or surgical devices and on which an appropriate biologically active substance would be immobilized could be of interest.